diff --git a/R/NcDataReader.R b/R/NcDataReader.R
index 9c85e331b04d1ce237f7269b2841c225541cc9e6..1c83d0af68c155c35bbe0dfb103342001fe3f594 100644
--- a/R/NcDataReader.R
+++ b/R/NcDataReader.R
@@ -210,6 +210,17 @@ NcDataReader <- function(file_path = NULL, file_object = NULL,
         } else if (grepl(' since ', units)) {
           # Find the calendar
           calendar <- attr(result, 'variables')[[var_name]]$calendar
+          # Calendar types recognized by as.PCICt()
+          cal.list <- c("365_day", "365", "noleap", "360_day", "360", "gregorian",  "standard", "proleptic_gregorian")
+
+          if (is.null(calendar)) {
+            warning("Calendar is missing. Use the standard calendar to calculate time values.")
+            calendar <- 'gregorian'
+          } else if (!calendar %in% cal.list) {
+            # if calendar is not recognized by as.PCICt(), forced it to be standard
+            warning("The calendar type '", calendar, "' is not recognized by NcDataReader(). It is forced to be standard type.")
+            calendar <- 'gregorian'
+          }
           if (calendar == 'standard') calendar <- 'gregorian'
 
           parts <- strsplit(units, ' since ')[[1]]
@@ -291,6 +302,7 @@ NcDataReader <- function(file_path = NULL, file_object = NULL,
               result <- result * 30 * 24 * 60 * 60  # day to sec
 
             } else {  #old code. The calendar is not in any of the above.
+              #NOTE: Should not have a chance to be used because the calendar types are forced to be standard above already.
               result <- result * 30.5
               result <- result * 24 * 60 * 60  # day to sec
             }
diff --git a/inst/doc/usecase/ex2_13_irregular_regrid.R b/inst/doc/usecase/ex2_13_irregular_regrid.R
index e09a691333ad40754315d98e548fda55ba7aa9f0..3fe3fc1d8cbb090eeb724daa294142759d29a3d1 100644
--- a/inst/doc/usecase/ex2_13_irregular_regrid.R
+++ b/inst/doc/usecase/ex2_13_irregular_regrid.R
@@ -10,8 +10,8 @@
 library(startR)
 library(s2dv)
 
-path <- paste0('/esarchive/exp/CMIP6/dcppA-hindcast/cmcc-cm2-sr5/cmip6-dcppA-hindcast_i1p1/',
-               'DCPP/CMCC/CMCC-CM2-SR5/dcppA-hindcast/$member$/Omon/$var$/gn/v20210312/',
+path <- paste0('/esarchive/exp/CMIP6/dcppA-hindcast/CMCC-CM2-SR5/',
+               'DCPP/CMCC/CMCC-CM2-SR5/dcppA-hindcast/$member$/Omon/$var$/gn/v20200101/',
                '$var$_*_s$sdate$-$member$_gn_$aux$.nc')
 
 data <- Start(dataset = path,
@@ -19,38 +19,35 @@ data <- Start(dataset = path,
               sdate = c('1960', '1961'),
               aux = 'all',
               aux_depends = 'sdate',
-              j = indices(2:361), # remove two indices to avoid white strips 
-              i = indices(2:291), # remove two indices to avoid white strips 
+              x = indices(2:361), # remove two indices to avoid white strips 
+              y = indices(2:291), # remove two indices to avoid white strips 
               time = indices(1:12),
               member = 'r1i1p1f1',
-              return_vars = list(j = NULL, i = NULL, 
-                                 latitude = NULL, longitude = NULL),
+              return_vars = list(nav_lat = NULL, nav_lon = NULL),
               retrieve = F)
 
 attr(data, 'Dimensions')
-#dataset     var   sdate     aux       j       i    time  member 
+#dataset     var   sdate     aux       x       y    time  member 
 #      1       1       2       1     360     290      12       1 
-dim(attr(data, 'Variables')$common$longitude)
-#  j   i 
-#360 290 
-dim(attr(data, 'Variables')$common$latitude)
-#  j   i 
-#360 290 
+dim(attr(data, 'Variables')$common$nav_lon)
+#  x   y 
+#362 292 
+dim(attr(data, 'Variables')$common$nav_lat)
+#  x   y 
+#362 292 
 
 func_regrid <- function(data) {
-  lons <- attr(data, 'Variables')$common$longitude
-  lats <- attr(data, 'Variables')$common$latitude
-  data <- s2dv::CDORemap(data, lons, lats, grid = 'r360x180', 
-                         method = 'bil', crop = FALSE)
+  lons <- attr(data, 'Variables')$common$nav_lon
+  lats <- attr(data, 'Variables')$common$nav_lat
+  data <- s2dv::CDORemap(data, lons[2:361, 2:291], lats[2:361, 2:291],
+                         grid = 'r360x180', method = 'bil', crop = FALSE)
   lons_reg <- data[['lons']]
   lats_reg <- data[['lats']]
   return(list(data = data[[1]], lats = lats_reg, lons = lons_reg))
 }
 
-#NOTE: The data transposes if target_dims are only 'j' and 'i'. 
-#      If only 'j' and 'i', output_dims will be 'lat', 'lon'.
 step <- Step(fun = func_regrid,
-             target_dims = list(data = c('j', 'i')),
+             target_dims = list(data = c('x', 'y')),
              output_dims = list(data = c('lon', 'lat'), 
                                 lats = 'lat', lons = 'lon'),
              use_attributes = list(data = "Variables"))
diff --git a/tests/testthat/test-Compute-irregular_regrid.R b/tests/testthat/test-Compute-irregular_regrid.R
index d92380acadb45a6353f286f68b4953331f9142c7..00a5c1d7f1b0afc5b39dc9addd970202866a8ecb 100644
--- a/tests/testthat/test-Compute-irregular_regrid.R
+++ b/tests/testthat/test-Compute-irregular_regrid.R
@@ -5,7 +5,7 @@ context("Irregular regriding in the workflow")
 test_that("1. ex2_13", {
 
 path <- paste0('/esarchive/exp/CMIP6/dcppA-hindcast/CMCC-CM2-SR5/',
-               'DCPP/CMCC/CMCC-CM2-SR5/dcppA-hindcast/$member$/Omon/$var$/gn/v20210312/',
+               'DCPP/CMCC/CMCC-CM2-SR5/dcppA-hindcast/$member$/Omon/$var$/gn/v20200101/',
                '$var$_*_s$sdate$-$member$_gn_$aux$.nc')
 suppressWarnings(
 data <- Start(dataset = path,
@@ -13,28 +13,27 @@ data <- Start(dataset = path,
               sdate = '1960',
               aux = 'all',
               aux_depends = 'sdate',
-              j = indices(2:361), # remove two indices to avoid white strips 
-              i = indices(2:291), # remove two indices to avoid white strips 
+              x = indices(2:361), # remove two indices to avoid white strips 
+              y = indices(2:291), # remove two indices to avoid white strips 
               time = indices(1),
               member = 'r1i1p1f1',
-              return_vars = list(j = NULL, i = NULL,
-                                 latitude = NULL, longitude = NULL),
+#              synonims = list(j = c(j, x), i = c(i, y)),
+              return_vars = list(#x = NULL, y = NULL,
+                                 nav_lat = NULL, nav_lon = NULL),
               retrieve = F)
 )
 func_regrid <- function(data) {
-  lons <- attr(data, 'Variables')$common$longitude
-  lats <- attr(data, 'Variables')$common$latitude
-  data <- s2dv::CDORemap(data, lons, lats, grid = 'r360x180',
+  lons <- attr(data, 'Variables')$common$nav_lon
+  lats <- attr(data, 'Variables')$common$nav_lat
+  data <- s2dv::CDORemap(data, lons[2:361, 2:291], lats[2:361, 2:291], grid = 'r360x180',
                          method = 'bil', crop = FALSE)
   lons_reg <- data[['lons']]
   lats_reg <- data[['lats']]
   return(list(data = data[[1]], lats = lats_reg, lons = lons_reg))
 }
 
-#NOTE: The data transposes if target_dims are only 'j' and 'i'. 
-#      If only 'j' and 'i', output_dims will be 'lat', 'lon'.
 step <- Step(fun = func_regrid,
-             target_dims = list(data = c('j', 'i')),
+             target_dims = list(data = c('x', 'y')),
              output_dims = list(data = c('lon', 'lat'),
                                 lats = 'lat', lons = 'lon'),
              use_attributes = list(data = "Variables"))
@@ -55,11 +54,11 @@ c(lon = 360, dataset = 1, var = 1, sdate = 1, aux = 1, time = 1, member = 1)
 )
 expect_equal(
 attr(data, 'Dimensions'),
-c(dataset = 1, var = 1, sdate = 1, aux = 1, j = 360, i = 290, time = 1, member = 1)
+c(dataset = 1, var = 1, sdate = 1, aux = 1, x = 360, y = 290, time = 1, member = 1)
 )
 expect_equal(
 mean(res$data, na.rm = T),
-13.20951,
+8.782398,
 tolerance = 0.0001
 )
 expect_equal(
@@ -67,5 +66,10 @@ drop(res$data)[120,105:110],
 c(28.32521, 28.07044, 27.59033, 27.02514, 26.55184, 26.67090),
 tolerance = 0.0001
 )
+expect_equal(
+range(res$data),
+c(-1.799982, 31.130471),
+tolerance = 0.0001
+)
 
 })
diff --git a/tests/testthat/test-Start-calendar.R b/tests/testthat/test-Start-calendar.R
index 7e2c7cfb6936ad47bee39d3badc2bbc78e4b063e..fde9c5e49074a03fade98c02a9c9669f1b84317e 100644
--- a/tests/testthat/test-Start-calendar.R
+++ b/tests/testthat/test-Start-calendar.R
@@ -211,7 +211,7 @@ suppressWarnings(
 
 expect_equal(
   attr(obs, 'Variables')$common$time[1], 
-  as.POSIXct('2005-05-16 12:00:00', tz = 'UTC')
+  as.POSIXct('2005-05-01', tz = 'UTC')
 )
 expect_equal(
   dim(attr(obs, 'Variables')$common$time),
diff --git a/tests/testthat/test-Start-reorder-lat.R b/tests/testthat/test-Start-reorder-lat.R
index 4133cf01e4b357350bb85dfc58212c472afc8060..2fe5de95b5f1c1dded90ad24f868e864c1704c92 100644
--- a/tests/testthat/test-Start-reorder-lat.R
+++ b/tests/testthat/test-Start-reorder-lat.R
@@ -872,13 +872,13 @@ res <- Start(dat = list(list(path=path_exp)),
 })
 
 ##############################################
-test_that("1-3. Selector type: indices(list)", {
-
-})
+#test_that("1-3. Selector type: indices(list)", {
+#
+#})
 ##############################################
-test_that("1-4. Selector type: indices(vector)", {
-
-})
+#test_that("1-4. Selector type: indices(vector)", {
+#
+#})
 ##############################################
 test_that("4-x-2-12-123-2-1-x", {
 
diff --git a/tests/testthat/test-Start-reorder-latCoarse.R b/tests/testthat/test-Start-reorder-latCoarse.R
index 4fc62ad03dbadae5c758a1012eac6e7593f8b8ce..6ca7b15c3c006db1137295003ce69ff8bc001bea 100644
--- a/tests/testthat/test-Start-reorder-latCoarse.R
+++ b/tests/testthat/test-Start-reorder-latCoarse.R
@@ -876,15 +876,15 @@ res <- Start(dat = list(list(path=path_exp)),
 })
 
 ##############################################
-test_that("1-3. Selector type: indices(list)", {
-
-})
+#test_that("1-3. Selector type: indices(list)", {
+#
+#})
 ##############################################
-test_that("1-4. Selector type: indices(vector)", {
-
-})
+#test_that("1-4. Selector type: indices(vector)", {
+#
+#})
 ##############################################
-test_that("1-4. Selector type: indices(vector)", {
-
-})
+#test_that("1-4. Selector type: indices(vector)", {
+#
+#})